Re: [PATCH v2 00/15] Krait clocks + Krait CPUfreq

From: Pramod Gurav
Date: Mon Sep 08 2014 - 05:43:01 EST

Hi Stephen,
Looks like one patch is missing from v1. Is this removed from v2
patchset from some reason?
ARM: Add Krait L2 register accessor functions

But there are references to this in v2 set and build fails while
compiling drivers/clk/qcom/clk-krait.c.

Thanks and Regards
Pramod

On Saturday 06 September 2014 04:17 AM, Stephen Boyd wrote:
> These patches provide cpufreq scaling on devices with Krait CPUs.
> In Krait CPU designs there's one PLL and two muxes per CPU, allowing
> us to switch CPU frequencies independently.
>
> secondary
> +-----+ +
> | QSB |-------+------------|\
> +-----+ | | |-+
> | +-------|/ |
> | | + |
> +-----+ | | |
> | PLL |----+-------+ | primary
> +-----+ | | | +
> | | +-----|\ +------+
> +-------+ | | | \ | |
> | HFPLL |----------+-----------------| |-----| CPU0 |
> +-------+ | | | | | | |
> | | | +-----+ | / +------+
> | | +-| / 2 |---------|/
> | | +-----+ +
> | | secondary
> | | +
> | +------------|\
> | | |-+
> +---------------|/ | primary
> + | +
> +-----|\ +------+
> +-------+ | \ | |
> | HFPLL |----------------------------| |-----| CPU1 |
> +-------+ | | | | |
> | +-----+ | / +------+
> +-| / 2 |---------|/
> +-----+ +
>
> To support this in the common clock framework we model the muxes,
> dividers, and PLLs as different clocks. CPUfreq only interacts
> with the primary mux (farthest right in the diagram). When CPUfreq
> sets a rate, the mux code finds the best parent that can provide the rate.
> Due to the design, QSB and the top PLL are always a fixed rate and thus
> only support one frequency each. These sources provide the lowest
> frequencies for the CPUs. The HFPLLs are where we can make the CPU go
> faster (GHz range). Sometimes we need to run the HFPLL twice as
> fast and divide it by two to get a particular frequency.
>
> When switching rates we can't leave the CPU clocked by the HFPLL because
> we need to turn off the output of the PLL when changing its frequency.
> This means we have to switch over to the secondary mux and use one of the
> fixed sources. This is why we need something like the safe parent patch.
>
> I plan to submit the DTS changes through arm-soc, but I've included everything
> here to make it easier to pick things up for testing, etc. Please note
> that these patches rely on the Krait L2 accessor patch I posted a while back
> in another series[1]. This also relies on the cpufreq-generic patchset from
> Viresh[2]. If anything can be picked up right now it would be better
> to reduce the churn over time as other pieces settle. The series gets
> progressively more controversial as it goes on, so I hope that things
> near the beggining will be picked up earlier.
>
> Changes since v1:
> * Added IPQ and APQ8064 support
> * Switched to cpufreq-generic
> * Added OPP parsing from DT (need to write binding though)
> * New patches to make clk-generic.c go away
> * Made mux and divider reusable for non-MMIO devices
> * Added a mux_determine_rate_closest (not sure if this is really needed)
> * Added unregistration of muxes
> * New patch to avoid sending high frequencies down to devices using clocks
>
> TODO:
> * Add Krait regulator voltage scaling (not strictly necessary)
> * Document DT bindings
> * Use a new efuse/eeprom API instead of hardcoding the location in the driver
> * Add some thermal awareness
>
>
> Stephen Boyd (15):
> clk: mux: Add unregistration API
> clk: mux: Split out register accessors for reuse
> clk: Add __clk_mux_determine_rate_closest
> clk: divider: Make generic for usage elsewhere
> clk: Add safe switch hook
> clk: Avoid sending high rates to downstream clocks during set_rate
> clk: qcom: Add support for High-Frequency PLLs (HFPLLs)
> clk: qcom: Add HFPLL driver
> clk: qcom: Add MSM8960/APQ8064's HFPLLs
> clk: qcom: Add IPQ806X's HFPLLs
> clk: qcom: Add support for Krait clocks
> clk: qcom: Add KPSS ACC/GCC driver
> clk: qcom: Add Krait clock controller driver
> cpufreq: Add module to register cpufreq on Krait CPUs
> ARM: dts: qcom: Add necessary DT data for Krait cpufreq
>
> arch/arm/boot/dts/qcom-apq8064.dtsi | 230 +++++++++++++++++
> arch/arm/boot/dts/qcom-msm8960.dtsi | 49 ++++
> arch/arm/boot/dts/qcom-msm8974.dtsi | 311 ++++++++++++++++++++++-
> drivers/clk/clk-divider.c | 197 +++++++++------
> drivers/clk/clk-mux.c | 91 ++++---
> drivers/clk/clk.c | 133 +++++++---
> drivers/clk/qcom/Kconfig | 28 +++
> drivers/clk/qcom/Makefile | 5 +
> drivers/clk/qcom/clk-hfpll.c | 253 +++++++++++++++++++
> drivers/clk/qcom/clk-hfpll.h | 54 ++++
> drivers/clk/qcom/clk-krait.c | 166 +++++++++++++
> drivers/clk/qcom/clk-krait.h | 49 ++++
> drivers/clk/qcom/gcc-ipq806x.c | 83 +++++++
> drivers/clk/qcom/gcc-msm8960.c | 172 +++++++++++++
> drivers/clk/qcom/hfpll.c | 110 +++++++++
> drivers/clk/qcom/kpss-xcc.c | 94 +++++++
> drivers/clk/qcom/krait-cc.c | 357 +++++++++++++++++++++++++++
> drivers/cpufreq/Kconfig.arm | 9 +
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/qcom-cpufreq.c | 199 +++++++++++++++
> include/dt-bindings/clock/qcom,gcc-msm8960.h | 2 +
> include/linux/clk-private.h | 2 +
> include/linux/clk-provider.h | 32 ++-
> 23 files changed, 2486 insertions(+), 141 deletions(-)
> create mode 100644 drivers/clk/qcom/clk-hfpll.c
> create mode 100644 drivers/clk/qcom/clk-hfpll.h
> create mode 100644 drivers/clk/qcom/clk-krait.c
> create mode 100644 drivers/clk/qcom/clk-krait.h
> create mode 100644 drivers/clk/qcom/hfpll.c
> create mode 100644 drivers/clk/qcom/kpss-xcc.c
> create mode 100644 drivers/clk/qcom/krait-cc.c
> create mode 100644 drivers/cpufreq/qcom-cpufreq.c
>
> [1] http://lkml.iu.edu/hypermail/linux/kernel/1404.0/02636.html
> [2] git://git.linaro.org/people/viresh.kumar/linux cpufreq/cpu0-krait-v3
>
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